Tympanic membrane pressure equalization tube delivery system

ABSTRACT

Systems and methods are provided for automatically forming an incision in a tympanic membrane of an ear and placing a tympanic membrane pressure equalization tube into the incision. The systems include a housing with a shaft extending therefrom. A mechanism is disposed within the housing. A distal end of the shaft is placed against a tympanic membrane, and the mechanism is triggered to causes the tympanic membrane to be automatically incised and dilated and a tympanic membrane pressure equalization tube to be placed in the dilated incision.

This application claims benefit of provisional application Ser. No.61/225,893, filed Jul. 15, 2009, the disclosure of which is expresslyincorporated by reference herein.

BACKGROUND OF THE INVENTION

The present invention is generally related to medical devices andapparatus. In particular, the invention provides systems and methods fordelivering a pressure equalization tube to a tympanic membrane of anear.

Otitis media is among the most common diagnoses made by pediatricians. Amajority of children may have at least one episode of otitis media(“earache”) prior to their third birthday. Otitis media is often causedby an inability of the eustachian tube to drain fluid from the middleear. Otitis media is often treated with antibiotics.

A significant number of children exhibit recurrent episodes of otitismedia and/or otitis media with effusion. Treatment of these more severecases often involves the placement of a tympanostomy tube through thetympanic membrane to provide adequate drainage of the middle ear andreduce the likelihood of future infections. Tympanostomy tubes providefluid communication between the middle and outer ear (e.g., pressureequalization) and typically fall out spontaneously within about a yearof placement. Tympanostomy tube placement is among the most frequentsurgical procedures performed in the pediatric population. It has beenestimated that more than a million tympanostomy tubes may be placed eachyear, with typical patients being between about 18 months and 7 years ofage at the time of the procedure.

Tympanostomy tube placement is typically performed in an out-patientsurgery setting under general anesthesia. The physician typically firstexamines the external auditory canal and tympanic membrane undermicroscopic visualization through a hand-held conical shaped speculum.The physician then makes an incision in the tympanic membrane (a“myringotomy”), typically using a standard, small profile scalpel whichthe physician advances through the conical speculum. In many cases, thephysician will then place the tympanostomy tube through the tympanicmembrane, typically using a basic tool for holding and advancing thetube into the myringotomy. The physician may then pass a suction devicethrough the tube, into the middle ear, to aspirate fluid/effusion fromthe middle ear.

A wide variety of tympanostomy tubes is commercially available, and astill wider variety of other tubes has been proposed. Systems have alsobeen proposed to both perform the myringotomy and deploy thetympanostomy tube with a single treatment assembly. In recent years,more complex and expensive systems have been proposed for diagnosis ortreatment of the tissues of the ear, including systems using laserenergy for forming a myringotomy, video systems for imaging of the earcanal, and the like. These various proposed alternatives fortympanostomy tubes and tube placement systems have met with varyingdegrees of acceptance. Some proposed alternatives have been overlycomplex, overly expensive and/or ineffective. Thus, have primarily usedstandard tubes and tube placement procedures and devices.

A standard tympanostomy tube placement procedure is both effective andquite safe. Nonetheless, further improvements would be desirable. Forexample, the standard tube placement procedure described above requiresmultiple tools (speculum, scalpel, tube placement device) and usuallyrequires the patient to be under general anesthesia. Tympanostomy tubeplacement error can occur due to using multiple operator-performed stepsand devices, and/or patient movement. The likelihood of error isincreased when operating on young children under local anesthesia, asthey often find it difficult to remain in a stationary position for anextended period of time.

One disadvantage of currently available tube placement methods is thatthe tympanostomy tubes may fall out of the tympanic membrane sooner thanwould be ideal. This may be due to the fact that the myringotomy must bemade large enough to allow the distal flange on a standard tympanostomytube to pass through it, and thus the typical myringotomy may be largerthan ideal for holding the tube in place.

Another disadvantage of currently available tube placement methods isthat the myringotomy needed to insert the tympanostomy tube isrelatively large and may cause increased scaring during the healingprocess.

In light of the above, it would be desirable to provide improveddevices, systems, and methods for delivering a pressure equalizationtube to a tympanic membrane. It would generally be beneficial if theseimprovements facilitated tympanostomy tube placement without requiringmultiple devices and operator-performed steps. At least some of theseadvantages may be provided by the embodiments described herein.

BRIEF SUMMARY OF THE INVENTION

The present invention provides systems and methods for automaticallypuncturing and delivering a tympanic membrane equalization tube (i.e.,tympanostomy tube) into a tympanic membrane.

In one aspect, a system is provided for delivering a pressureequalization tube. The system includes a housing including a handle. Anelongate shaft assembly is coupled with the housing. The shaft assemblyincludes an outer shaft having a blunt (atraumatic) distal tip portion.The distal tip portion of the elongate shaft has an inner diameter thatmay be equal to or larger than the inner diameter of the remainder ofthe outer shaft. A cutter is linearly moveable within the elongateshaft. A pusher is slidably disposed over the cutter within the elongateshaft. A pressure equalization tube is slidably disposed about thecutter at a distal end of the pusher. A shield is slidably disposed overthe pusher and the pressure equalization tube. A dilator is slidablydisposed over the shield. In one alternate embodiment, the cutter andthe dilator may be combined as one feature as hereinafter described.

The system also includes a cam assembly. The cam assembly includes a camshaft rotationally coupled within the housing. The cam shaft includes afirst cam profile, second cam profile, a third cam profile, and a fourthcam profile. A first cam follower is moveably coupled to the first camprofile. The first cam follower is attached to the cutter. A second camfollower is moveably coupled to the second cam profile. The second camfollower is attached to the pusher. A third cam follower is moveablycoupled to the third cam profile. The third cam follower is attached tothe shield. A fourth cam follower is moveably coupled to the fourth camprofile. The fourth cam follower is attached to the dilator.

In one embodiment, a spring may be biased between the housing and thecam shaft. The spring has a wound position, which places torsion on thecam shaft, and a released position.

A release button may be moveably coupled to the cam shaft. The releasebutton has a first position, which maintains the spring in the woundposition, and a second position, which allows the spring to move intothe released position. When the release button is moved into thereleased position, the spring is released to move the cam shaft andcause the cam followers to linearly move respective portions of theshaft assembly to form an incision in a tympanic membrane using thecutting member, dilate the incision using the dilator, and advance thepressure equalization tube out of the shield and into the incision usingthe pusher.

In another aspect, a method is provided for forming an incision andplacing a pressure equalization tube in a tympanic membrane of an ear.The method includes contacting a blunt (atraumatic) distal end of ashaft of a tube delivery device with a tympanic membrane. A cutter isadvanced out of the shaft distal end to form an incision in the tympanicmembrane. A dilator is disposed over at least a portion of the cutter. Ashield disposed over the cutter and within the dilator is advanced outof the shaft distal end and into the incision to dilate the dilator. Theshield is disposed over a pressure equalization tube. The cutter isretracted into the shaft. The shield is retracted into the shaft,thereby releasing a distal flange of the pressure equalization tube suchthat it assumes an expanded configuration. The pressure equalizationtube is pushed out of the shield using a pusher disposed within theshield, thereby releasing a proximal flange of the pressure equalizationtube such that it assumes an expanded configuration. After being pushedout of the shield, a middle portion of the pressure equalization tube isdisposed within the incision in the tympanic membrane and the distal andproximal flanges are disposed on opposite sides of the incision.

Advantageously, such systems and methods facilitate automatic deliveryof a tympanic membrane equalization tube with minimal steps to beperformed by an operator, such as advancing the system into an ear canaland triggering a release button.

For a further understanding of the nature and advantages of theinvention, reference should be made to the following description takenin conjunction with the accompanying figures. However, each of thefigures is provided for the purpose of illustration and description onlyand is not intended to limit the scope of the embodiments of the presentinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A through 1G are views of delivery systems for delivering atympanic membrane equalization tube into a tympanic membrane, accordingto two embodiments of the invention.

FIGS. 1H and 1I are exploded views of the delivery systems of FIGS. 1Athrough 1D and FIGS. 1E though 1G respectively.

FIGS. 1J/1K and 1N/1O are a partial side views of internal portions ofthe delivery systems of FIGS. 1A though 1D and FIGS. 1E through 1G,respectively.

FIGS. 1L and 1M are views of internal portions of the cam/switchinterface of the delivery system depicted in FIGS. 1E through 1G.

FIG. 1P is a cross-sectional view of the distal tip of the deliverysystems of FIGS. 1A through 1G.

FIG. 2A is a displacement and operational diagram, according to oneembodiment of the invention.

FIG. 2-B is a displacement and operational diagram, according to oneembodiment of the invention.

FIG. 3 is perspective view of a delivery system for delivering atympanic membrane equalization tube into a tympanic membrane, accordingto one embodiment of the invention.

FIGS. 4A through 4D are perspective and side views of an integratedcutting member and dilator, according to two embodiments of theinvention.

FIG. 4E is a cross-sectional view of a distal tip of a delivery systemin use, according to one embodiment of the invention.

FIG. 4F depicts a schematic of a negative pressure actuation system,according to one embodiment of the invention.

FIGS. 5A and 5B are perspective and side views, respectively, of atympanic membrane equalization tube, according to one embodiment of theinvention.

FIG. 5C is a perspective view of a tympanic membrane equalization tube,according to one embodiment of the invention.

FIGS. 5D through G are perspective views of tympanic membraneequalization tubes, according to multiple embodiments of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The embodiments of the invention are intended to provide systems forautomatically puncturing and delivering a tympanic membrane equalizationtube into a tympanic membrane. According to embodiments of theinvention, tympanic membrane equalization tube delivery systemsgenerally include a housing with a dedicated handgrip, or a graspablehousing. A shaft extends out of the housing to access the tympanicmembrane, and a tympanic membrane equalization tube is loaded within thetip of the shaft. An internal spring loaded cam-based mechanism islocated within the housing and coupled to a button. The mechanism can betriggered to initiate a fast and automatic process which punctures thetympanic membrane, and delivers the tympanic membrane equalization tube.The tympanic membrane equalization tube is a grommet like device whichis folded and/or compressed within the tube, and recovers its shape whendelivered into the tympanic membrane.

In use, an operator grasps the housing by the handgrip and brings thetip of the shaft into contact with the tympanic membrane. The operatorthen triggers the cam-based mechanism by pressing the button. The systemthen automatically punctures and inserts the tympanic membraneequalization tube into the tympanic membrane. Thus, a simple andeffective delivery system is provided, which requires minimal operatorsteps for use.

Embodiments of the invention are compatible for use with a suite ofmedical devices for visualizing, guiding other medical devices,delivering a tympanic membrane equalization tube, puncturing thetympanic membrane, and anesthetizing the tympanic membrane. Examples ofsuch medical devices are shown in co-assigned U.S. patent applicationSer. No. 11/749,733, the entirety of which is incorporated by reference.Accordingly, aspects of U.S. patent application Ser. No. 11/749,733 maybe integrated, combined, and used in conjunction with the embodimentsdisclosed herein.

Exemplary Configurations of the Delivery System:

Two exemplary systems are described below and shown in separate figures(FIGS. 1A through 1G). Where possible, the same numbering scheme is usedto identify each system's components. Clarification is added when thecomponents of the systems vary in function.

The system represented by FIGS. 1E through 1G have several advantagesover the system represented by FIGS. 1A through 1D. The housing designprovides a more stable and ergonomic grip enhancing device stabilityduring usage. The spring 114 is moved to the proximal end of thedelivery system 100, which aids in the more balanced and stable deliveryof the tympanic membrane equalization tube.

FIGS. 1A through 1G shows a delivery system 100 for delivering atympanic membrane equalization tube into a tympanic membrane, accordingto one embodiment of the invention. The delivery system 100 includes ahousing 102 with a handle, or a provision for a handhold such asdepicted in the overall design depicted in FIGS. 1E through 1G. A shaftassembly 104 is attached to the housing 102. The shaft assembly 104 isconstructed from one or more elongate tubes, and is configured to havean outer diameter which is small enough (e.g., 2 mm) to navigate adistal portion of the shaft assembly into a tortuous path of an earcanal without requiring significant deformation of the ear canal orshaft assembly 104. In many embodiments, the shaft assembly has apreformed curvature to facilitate access to the tympanic membrane. Insome embodiments the shaft assembly may be made of a malleablematerial(s), adjustable by the user to aid in navigating the ear canal.A tympanic membrane equalization tube (not shown) is preferably housedwithin the distal portion of the shaft assembly 104. A release button106 protrudes through housing 102. The release button 106 is configuredto release an internal mechanism which causes the shaft assembly 104 toautomatically puncture a tympanic membrane and also insert the tympanicmembrane equalization tube into the punctured tympanic membrane. In use,the delivery system 100 is used to bring the distal portion of the shaftassembly into contact, or near contact, with a tympanic membrane of anear of a patient. The release button 106 is then manipulated to releasean internal mechanism which causes the shaft assembly to automaticallyand swiftly puncture the tympanic membrane, and also swiftly deliver thetympanic membrane equalization tube into the punctured tympanicmembrane.

FIG. 1H/1I shows a partially exploded view of the delivery system 100.The housing 102 is made up of a first housing portion 108 and a secondhousing portion 110, which mate together in a clamshell manner. Acamshaft 112 is rotatably housed between the first housing portion 108and a second housing portion 110. The camshaft 112 is also coupled to aspring 114, which may be biased (i.e., wound) between the housing 102and camshaft 112. The shaft assembly 104 is movably attached to four camfollowers, 120 a, 120 b, 120 c, and 120 d, each of which are slidablyhoused within the housing 102 along an axis A-A of the shaft assembly104. The cam followers 120 a-d are configured as slidable blocks. Therelease button 106 is slidably moveable within a button housing 116,which is mounted or otherwise incorporated within the housing 102. Alink 118 is moveably connected between a portion of the camshaft 112 andthe release button 106. The release button 106 can move or release thelink 118 to disengage from the camshaft 112, and allow the spring 114 toat least partially unwind and rotate the camshaft 112, which in turnmoves the cam followers 120 a-d, which in turn moves portions of theshaft assembly 104 to automatically puncture the tympanic membrane, andalso deliver the tympanic membrane equalization tube into the puncturedtympanic membrane. Many embodiments can use other triggering mechanisms,for example, one or more fusable links may be activated by the button106. A fusable link can be activated to erode and disengage from thecamshaft 112. In some embodiments a counter balance spring 147 can beutilized to offset the loads transmitted from the spring 114 through thecamshaft 112 and link 118 to the release button 106. This allows therelease button 106 to move or release the link 118 with minimal force.Other embodiments may also include a lock tab 148 that holds the releasebutton in place during handling and helps avoid unintended actuation ofthe device.

FIG. 1J/1K shows a portion of the delivery system 100 with the secondhousing portion 110 removed. The first cam follower 120 a is connectedto a proximal portion of a cutting member 121 a. The cutting member 121a is an elongate wire or tube with a provision for puncturing (e.g. asharpened tip) a tympanic membrane at its distal end. The second camfollower 120 b is directly adjacent to the first cam follower 120 a. Thesecond cam follower 120 b is connected to a proximal portion of a pusher121 b. The pusher 121 b is an elongate tube within which the cuttingmember 121 a slidably resides. The third cam follower 120 c is connectedto a proximal portion of a shield 121 c. The shield 121 c is an elongatetube within which the pusher 121 b slidably resides. The fourth camfollower 120 d is connected to a proximal portion of dilator 121 d. Thedilator 121 d is an elongate tube with a distal tip capable of expandingfrom a narrow position to an expanded position. The shield 121 cslidably resides within the dilator 121 d. An outer shaft 121 e isattached to the first housing portion 108. The outer shaft 121 e is anelongate tube with a distal opening, and can be constructed from a stiffmaterial, such as stainless steel.

The four cam followers 120 a-d include pins 122 a-d and are housed incam follower chamber 130. Each pin 122 a-d is slidable within a track123 a-d. The tracks 123 a-d are profiled grooves in the circumference ofthe camshaft 112. As each pin 122 a-d is attached to a corresponding camfollower 120 a-d, movement of a pin 122 a-d moves the corresponding camfollower 120 a-d and a respective portion of the shaft assembly 104. Forexample, when the camshaft 112 is rotated, pin 122 a follows track 123a, and is moved parallel to axis A-A to translate rotational movement ofthe camshaft 112 into linear motion of the cutting member 121 a alongaxis A-A. Similarly, track 123 b corresponds with pusher 121 b; track123 c corresponds with shield 121 c; and track 123 d corresponds withdilator 121 d.

A trigger mechanism chamber 124 houses the button housing 116. Thetrigger mechanism chamber 124 includes an opening for the button 106 topass through. The first housing portion 108 is shown holding thecamshaft 112 within a camshaft chamber 126, which includes rotationalmounting points for the camshaft 112. A portion of the camshaft 112extends into a spring chamber 128, where the spring 114 mounts to thecamshaft 112. The spring 114 can be wound so as to be biased between thecamshaft 112 and a portion of the spring chamber 128. The cam followers120 a-d are linearly arranged within a follower chamber 128.

FIGS. 1L and 1M show further detail of an improved trigger mechanismthat provides more consistent actuation motion and force.

FIG. 1L shows a camshaft tooth 150 extending from an end of the camshaft112. A link tooth 151 extending from the link 118 inhibits rotationalmotion of the camshaft 112 when the link 118 is held in place by therelease button 106.

FIG. 1M shows a perspective view of the interface 152 between therelease button 106 and the link 118. Lateral movement of the releasebutton 106 disengages the interface 152 between the release button 106and link 118 allowing the link 118 to pivot about the link pin 132(shown in FIG. 1L) allowing the spring 114 to at least partially unwindand rotate the camshaft 112. As described above, the counter balancespring 147 can be utilized to offset the loads transmitted from thespring 114 through the camshaft 112 and link 118 to the release button106. This allows the release button 106 to move or release the link 118with minimal force.

FIG. 1N/1O shows a portion of the delivery system 100 with the firsthousing portion 108/110 removed. The interior of the second housingportion 110 is substantially similar to the first housing portion 108and includes internal members to form the trigger mechanism chamber 124,camshaft chamber 126, spring chamber 128 (not shown), and followerchamber 130, when mated to the first housing portion 108. The link 118is joined to second housing portion 110/108 by a link pin 132. The link118 pivots between the release button 106 and a portion of the camshaft112 about the link pin 132. The spring 114 (not shown) can be wound soas to be biased between the camshaft 112 and a portion of the springchamber 128 and kept in the biased position by the link 118. The button106 can be pressed to decouple the link 118 from the camshaft 112, whichin turn causes the wound spring 114 to unwind and rotate the camshaft112. The camshaft 112 will rotate until it encounters a physical stop inthe first or second housing portion 108, 110. The button 106 can becoupled to a safety mechanism (not shown), such as a slidable pin,button cover or lock tab which must be switched from an on position toan off position, or removed, in order to allow the button 106 to bepushed.

In many embodiments, the delivery system 100 includes provisions fornoise dampening to reduce shock to the patient. After the spring 114 isreleased, the camshaft 112 will rotate until it encounters a stop in thefirst or second housing portion 108, 110, which can result in anunwanted noise which can shock the patient. The camshaft 112 and spring114 can include lubrication and noise dampening members, such as arubber stop 149 (such as shown in FIG. 1I and FIG. 1K, for example). Thefirst or second housing portion can also use a non-concentric surface,instead of a sudden stop, which gradually brakes the camshaft 112. Soundbaffling in the housing 102 can also be used to muffle and/or directsound away from the ear. Sound tuning at a selected frequency andamplitude can also be employed directly prior to using the deliverysystem 100 to reduce shock to the patient. Introducing a noise usingsound tuning causes muscles connected to the stapes to contract andreduce noise transmission to the inner ear. Sound tuning can alsoinclude generating a noise that is gradually introduced to the patientto acclimate the patient to the noise created by the delivery system100, thus, reducing shock.

FIG. 1P shows a cross-sectional view of the distal end of the shaftassembly 104. The cutting member 121 a is a diamond shaped cutting head134 connected to an elongate wire 136. Preferably, the diamond shapedcutting head 134 is configured with multiple facets leading to a singlesharp point, which can easily puncture a tympanic membrane using minimalaxial force. The cutting member 121 a is not limited to use of thediamond shaped cutting head 134. In many embodiments, the cutting member121 a employs a knife edged tip or a coring/non-coring needle. Thecutting member 121A may also employ a wedge or planar shape with bevelededge, which may allow access to more sites of the tympanic membrane.Generally, the cutting member 121 a can utilize any properly sizedcutting head 134. In some embodiments, the shape of cutting head 134 mayfacilitate performing a myringotomy (i.e., incising a TM) withoutforming flaps in the TM.

The dilator 121 d has a folding tip 138 which is capable of expandingfrom a narrow position to an expanded position. The folding tip 138 hasa cone like shape when in the narrow position, as shown. The folding tip138 abuts the back of the diamond shaped cutting head 134 when in thenarrow position. The folding tip 138 can be formed by making a pluralityof triangular cuts at the distal end of a tube to form folding members,and folding the folding members into a cone. The folding tip 138generally only requires two folding members, while in this embodimentfour folding members are used.

The shield 121 c is a tube which is placed within the dilator 121 d andproximally to the folding tip 138. When the shield 121 c is moved in adistal direction, it can force open the folding tip 138. A straightenedtympanic membrane equalization tube 140 is placed within the shield 121c. The tympanic membrane equalization tube 140 is restrained within theshield 121 c, and proximal and distal flanges of the tube 140, which areforced into a straightened configuration within the shield 121 c, applya constant expansive force to the interior diameter of the shield 121 cto stay in place. The tympanic membrane equalization tube 140 can havean interior diameter greater than the outer diameter of the diamondshaped cutting head 134 to allow removal of the tympanic membraneequalization tube 140. The tympanic membrane equalization tube 140 canalso have an interior diameter equal to or smaller than the outerdiameter of the diamond shaped cutting head 134, as the tympanicmembrane equalization tube 140 may comprise an elastic material whichallows for slight deformation/stretching of the tympanic membraneequalization tube 140 during movement of the diamond shaped cutting head134. The pusher 121 b is a tube which is placed proximally to the foldedtympanic membrane equalization tube 140. The pusher 121 b can be moveddistally to push the folded tympanic membrane equalization tube 140 outof the shield 121 c.

The outer shaft 121 e surrounds the dilator 121 d and is stationary withrespect the movement of the other portions of the shaft assembly 104.The outer shaft 121 e provides axial stiffness to the shaft assembly104, and can be formed from a metal such as stainless steel. A tip 142is attached to the distal end of the outer shaft 121 e. The tip can becomposed of a clear material to allow visualization of the tube 140 aswell as anatomical structures abutting the delivery system 100 in orderto facilitate accurate placement of the tube 140. Alternatively, the tip142 may be formed from the same piece of material as the outer shaft 121e. The tip 142 includes an inner diameter which is greater than theinner diameter of the outer shaft. This larger inner diameter of the tip142 allows a proximal flange of the tympanic membrane equalization tube140 to open into its expanded/unconstrained configuration within the tip142 when advanced by the pusher 121 b. This expansion of the proximalflange within the tip 142 may help prevent advancement of the entireequalization tube 140 through a myringotomy into the middle ear.

In some embodiments, a pressure/contact/distance sensor may be coupledto the tip 142. The sensor provides a signal when the tip 142 contactsor is near the tympanic membrane. The signal may trigger a visualindicator (e.g., an LED) on the housing 102 to indicate that the tip 142is in a proper position for inserting the tympanic membrane equalizationtube 140 into the tympanic membrane. The sensor can be a piezoelectric,optical, capacitive based sensor, or any other suitable sensor. Thesignal may also trigger other operations, such triggering movement ofthe camshaft 112, or a sound tuning operation as described herein.

In some embodiments, the distal portion of the shaft assembly 104 may beconfigured to better access the tympanic membrane. The tympanic membranehas a conical shape and is angled with respect to the axis of the earcanal. Accordingly, the distal end of the shaft assembly 104 may contactthe tympanic membrane at non-optimal angle (e.g. non-perpendicular). Inthis case, the operator may mistakenly stop short of applying sufficientpressure to the tympanic membrane to ensure complete delivery of thepressure equalization (PE) tube. In other cases, the operator mayovercompensate and place too much pressure on the tympanic membrane,thus, driving the tip of the shaft assembly 104 through the tympanicmembrane. To overcome these situations, the distal portion of the shaftassembly 104 can incorporate an angle such that the distal tip of theshaft assembly 104 can have better access to the tympanic membrane. Inuse, the operator can either rotate all or a portion of the system 100to place the distal tip of the shaft assembly 104 in an optimal positionwith respect to the tympanic membrane. In some embodiments, the shaftassembly 104 is malleable so that the operator can bend the shaftassembly 104 to a desired position.

In some embodiments, the outer shaft 121 e of the shaft assembly 104includes a flexible zone, such that when the distal tip of the shaftassembly 104 presses against the tympanic membrane, the distal tip ofthe shaft assembly 104 automatically adjusts to an optimal position. Forexample, a portion of the outer shaft 121 e can utilize a springsection, accordion section, or stent-like scaffold which elastically orplastically compresses when the distal tip of the shaft assembly 104presses against the tympanic membrane. Compression of the tip can givethe operator visual feedback as to the amount of pressure being appliedto the tympanic membrane. In some embodiments, the outer shaft 121 e hasa laser cut portion removed such that a helical section exists between amid-portion of the outer shaft 121 e and a distal end of the outer shaft121 e. The helical section can be configured to flex only whensufficient pressure has been applied, thus, the operator would need toapply enough pressure to completely compress at least one side of thehelical section to ensure a proper tympanic membrane equalization tube140 delivery. In some embodiments, all or discrete portions of the shaftassembly 104 can include similar flexible zones and/or be constructedfrom flexible materials, for example, the cutting member 121 a may beconstructed from a super-elastic material (e.g., nickel-titanium alloy).

Methods of Operating of the Exemplary Delivery System:

FIG. 2A shows a displacement diagram 200 of the camshaft 112 andcorresponding simplistic views of the distal tip of the shaft assembly104 placed within an ear canal, with the tip 142 against a tympanicmembrane TM. The displacement diagram 200 shows patterns of respectivetracks 123 a-d along axis X and Y. Axis Y represents the lineardisplacement of the tracks 123 a-d along the circumference of thecamshaft 112. Axis X represents the linear displacement of the tracksperpendicular axis Y.

As previously noted, the pins 122 a-d follow movement of the tracks 123a-d. The pins 122 a-d are attached to corresponding cam followers 120a-d. Thus, movement of the pins 122 a-d results in movement of thecorresponding cam followers 120 a-d and respective movement of portionsof the shaft assembly 104 along axis A-A, which is parallel to Axis X.Each track 123 a-d is shown with a numeric displacement value at thevarious positions. The numeric displacement values are the distances inmillimeters between the distal end of the tip 142 and the distal mostposition of the related shaft assembly 104 portions 121 a-d. The viewsof the distal tip of the shaft assembly 104 show incremental positioningwith respect to the displacement diagram, however, the movement of theshaft assembly 104 and camshaft 112 is one continuous movement. Invarious embodiments, the camshaft 112 may take between about 5milliseconds and about 500 milliseconds to rotate from the initialposition to a final position, after the button 106 has been pressed. Inother words, it may take from about 5 to about 500 milliseconds from thetime the button 106 is pressed until a pressure equalization tube 140 isdeployed in a TM using the device 100. In some embodiments, this timeperiod may be between about 30 milliseconds and about 250 milliseconds,with average times of between about 100 milliseconds and about 130milliseconds. In other embodiments, the time period may be outside theranges listed above.

1. Initial Camshaft Position:

At the initial position of the camshaft 112, the shaft assembly 104 ispositioned as shown in FIG. 1P. At this position, the button 106 has notbeen pressed to release the wound spring 114. The shaft assembly 104 hasbeen advanced into the ear canal such that the tip 142 abuts a portionof the tympanic membrane TM. At the initial camshaft position, thecutting member 121 a is 0.25 mm behind (i.e., proximal) the extremedistal end of the tip 142; the pusher 121 b is 7.04 mm behind the tip142; the shield 121 c is 4.09 mm behind the tip 142; and the dilator 121d is 1.68 mm behind the tip.

2. First Camshaft Position:

At a first camshaft position, the button 106 has been pressed to releasethe wound spring 114 which rotates the camshaft 112 from the initialcamshaft position to the first camshaft position. Accordingly, asdescribed herein, movement of the camshaft causes the cam followers 120a-d to move respective portions of the shaft assembly 104. At the firstcamshaft position the cutting member 121 a punctures the tympanicmembrane TM and the dilator 121 d follows to dilate the puncture site toa larger diameter. The pusher 121 b and shield 121 c also advance, butremain behind the tip 142. At the first camshaft position the cuttingmember 121 a is 2.79 mm ahead (i.e., distal) of the extreme distal endof the tip 142; the pusher 121 b is 1.66 mm behind the tip 142; theshield 121 c is 1.04 mm behind the tip 142; and the dilator 121 d is1.37 mm ahead of the tip 142.

3. Second Camshaft Position:

The camshaft 112 rotates from the first camshaft position to a secondcamshaft position. At the second camshaft position, the shield 121 cadvances past the tip 142 to open the folding tip 138 of the dilator 121b and further dilate the puncture site, and the cutting member 121 aretracts behind the dilator 121 b. The pusher 121 b also advances, butremains behind the tip 142. At the second camshaft position the cuttingmember 121 a is 0.58 mm ahead of the extreme distal end of the tip 142;the pusher 121 b is 1.55 mm behind the tip 142; the shield 121 c is 0.66mm ahead of the tip 142; and the dilator 121 d remains 1.37 mm ahead ofthe tip 142.

4. Third Camshaft Position:

The camshaft 112 rotates from the second camshaft position to a thirdcamshaft position. At the third camshaft position, the cutting member121 a and dilator 121 d retract behind the tip 142. The shield 121 calso retracts, while the pusher 121 b advances to partially push thetympanic membrane equalization tube 140 out of the shield 121 c. Amedial flange 144 (or “distal flange”) of the tympanic membraneequalization tube 140 is pushed out of the shield 121 c to expand medial(or “distal”) to the tympanic membrane. At the third camshaft positionthe cutting member 121 a is 1.78 mm behind the extreme distal end of thetip 142; the pusher 121 b is 1.45 mm behind the tip 142; the shield 121c is 1.02 mm behind the tip 142; and the dilator 121 d is 1.23 mm behindthe tip 142.

5. Final Camshaft Position:

The camshaft 112 rotates from the third camshaft position to a finalcamshaft position. At the final camshaft position, the cutting member121 a, shield 121 c, and dilator 121 d remain stationary with respect tothe third camshaft position. The pusher 121 b advances to a finalposition, but remains behind the tip 142, to push a lateral flange 146(or “proximal flange”) of the tympanic membrane equalization tube 140outside of the shield 121 c to expand within the tip 142 of the device100 and lateral (or “proximal”) to the tympanic membrane. At the finalcamshaft position the cutting member 121 a is 1.78 mm behind the extremedistal end of the tip 142; the pusher 121 b is 0.84 mm behind the tip142; the shield 121 c is 1.02 mm behind the tip 142; and the dilator 121d is 1.23 mm behind the tip 142.

An alternative embodiment for the camshaft design is depicted in FIG.2B. Reference to the above description of the various camshaft positionsare applicable to this embodiment with the exception of slightlymodified advancement points along the tracks of the cam as noted in thefigure. The most noticeable variation is that shield 123 c retractsfurther back into the shaft in the final camshaft position relative tothe camshaft depiction of FIG. 2A.

When the pressure equalization tube 140 has been successfully placed,with the medial flange 144 and lateral flange 146 flanking the TM, theshaft assembly 104 may then be withdrawn from the ear canal, leaving thetube 140 behind. The above steps may then be repeated, if desired, inthe patient's other ear using a second device 100 or by reloading thefirst device 100 with another equalization tube 140. In someembodiments, device 100 may be reloadable, while in alternativeembodiments device 100 may be a one-use device only. Thus, according tothe method described above, by simply positioning the delivery system100 within the ear canal, with the tip 142 against the tympanic membraneTM, and pressing button 106, the delivery system 100 both punctures thetympanic membrane TM and also delivers the tympanic membraneequalization tube 140 in one effective movement.

Alternative Structure of the Delivery System:

Referring now to FIG. 3, in one alternative embodiment, a tympanicmembrane pressure equalization tube delivery system 300 may include apencil grip 302 handle and a trigger 304 for activating the deliverysystem 300. The delivery system 300 may be configured similarly to thedelivery system 100, and may include a substantially similar internaltympanic membrane equalization tube delivery mechanism and shaftassembly. However, the delivery system 300 features the pencil grip 302which may be ergonomically similar to grips of standard myringotomyspears. The trigger 304 may be placed in any convenient ergonomiclocation, such as on the top of the system 300, as shown. In otheralternative embodiments, other handle and/or trigger configurations maybe used including the configuration depicted in FIGS. 1E through 1G.

With reference now to FIGS. 4A-4D, in two alternative embodiments, a TMtube delivery device may include a cutting dilator 400 at its distalend, rather than including a separate cutter and dilator. In otherwords, the cutting dilator 400 integrates the cutting member 121 a anddilator 121 d. The cutting dilator 400 is capable of puncturing atympanic membrane and also expanding to dilate a puncture site. Thecutting dilator 400 includes a plurality of fingers 402 arranged as acone. In the examples shown, four fingers 402 are used. More fingers 402generally allow easier expansion. At least one of the fingers 402includes a sharpened tip (FIGS. 4A and 4B) or cutting blade (FIGS. 4Cand 4D) for puncturing the tympanic membrane. The cutting dilator 400may be made from any suitable material that can be expanded from aclosed to a dilated configuration. For example, in one embodiment, thedilator 400 may be formed from a super-elastic nickel-titanium alloy. Inanother embodiment, the cutting dilator 400 may be formed from amalleable material, such that when the cutting dilator 400 dilates itretains approximately the dilated configuration.

FIG. 4E shows, in one alternative embodiment, an alternate construction,and method for use, for the distal end of the shaft assembly 404. Theshaft assembly 404 is constructed similarly to the shaft assembly 104shown in FIG. 1E. However, outer shaft 406 includes an outer wall 408and an inner wall 410, with a space 412 therebetween. The space 412 canbe fluidly connected to a negative air pressure source, which isconnected to the housing 102. The housing 102 can include an additionaltrigger device for enabling negative pressure to be applied to the space412. Negative pressure may also be enabled and/or disabled by anautomatic process, for example by port/valve triggered by the rotationof the camshaft 112. The outer shaft 406 can be a constructed, forexample, from two individual tubes, from a double walled extrusion witha connecting member therebetween, or from a single walled extrusionincluding a plurality of lumens. The outer shaft 406 remains smallenough in diameter, compared to the outer shaft 121 e, to enablevisualization and access through typical ear canal, and also reach anyquadrant of TM. The outer shaft 406 can provide a suction force to thetympanic membrane TM in order to elevate a portion of the tympanicmembrane TM away from a normal position.

Elevating the tympanic membrane can result in reduction of noiseadmittance during penetration of the cutting member 136. Elevating thetympanic membrane can also provide local stabilization of a target siteto enhance the reliability of use of the system 100, thus preventingaccidental deviation or slipping of the cutting member 136 duringpenetration. Elevation of tissue, can also be especially useful forpatients with retraction pockets. Long term retraction of the eardrum,caused by negative pressure in the middle ear, will cause erosion of theear canal and formation of a deep pocket. Eventually the pocket may trapskin, forming a skin cyst or cholesteatoma. Further progression ofretraction pockets can cause destruction of the tympanic membrane.Tissue elevation enhances safety by providing additional space away fromanatomical structures distal to the tympanic membrane for penetrationand placement of the tympanic membrane pressure equalization tube 140.Accordingly, tissue elevation also allows a larger patient population tobe treated, as a significant portion of patients who require placementof tympanostomy tubes have some degree of retraction.

In use, with reference to FIGS. 2A/2B and 4E, negative pressure may beapplied to the space 412 of the outer shaft 406, before pressing button106. The distal end of the outer shaft 406 may brought into contact, ornear contact, with the tympanic membrane TM before, or after applyingnegative pressure. The negative pressure causes the tympanic membrane TMto temporarily attach to the distal end of the outer shaft 406. Thetympanic membrane TM may then be elevated by pulling or placing thedistal end of the outer shaft 406 in a proximal position (i.e., towardsthe outer ear) from the current position of the tympanic membrane TM.Tissue elevation is illustrated by movement of the dotted lines to solidlines, which represent the tympanic membrane TM in pre- andpost-elevation positions, respectively. Thus, after elevation,additional space is provided away from anatomical structures distal tothe tympanic membrane TM, for penetration and placement of the tympanicmembrane pressure equalization tube 140. After the tympanic membrane TMhas been elevated to a desired position, the button 106 may be pressedto initiate automatic placement of the tympanic membrane pressureequalization tube 140 in the tympanic membrane TM, while negativepressure is continually applied to the tympanic membrane TM. After thetympanic membrane pressure equalization tube 140 is placed, applicationof negative pressure to the space 412 of the outer shaft 406 can bestopped, thus releasing the tympanic membrane TM from the outer shaft406. Alternatively, application of negative pressure to the space 412 ofthe outer shaft 406 can be stopped at other points of the method shownin FIGS. 2A/2B, for example after the medial flange 144 of the tympanicmembrane equalization tube 140 is pushed out of the shield 121 c toexpand medial to the tympanic membrane.

An addition to the above alternate embodiment would include using theapplied negative pressure as a means to actuate the device. FIG. 4Fdepicts a schematic of a potential negative pressure actuation system. Apiston or bellows 400 within the delivery system 100 connected to thelink 118 could move upon exposure to negative pressure and trigger thecamshaft 112 rotation. The negative pressure on the piston or bellowscould be generated when the tip 142 of the device attains appositionagainst the tympanic membrane thus ensuring the device position relativeto the tympanic membrane.

The system includes a vacuum chamber 402 that has a contiguous, sealedlumen providing communication between the device tip 142 (that comesinto contact with the tympanic membrane) and the proximal end of thedelivery system 100. The chamber includes a vacuum actuated triggermechanism such as vacuum cylinder 404 and piston 400 and a vacuum port406 that can be attached to a vacuum source such as through a vacuumline normally available in an operating room or other clinical setting.

Advantages of the above embodiment include more accurate and consistentPE tube deployment into the tympanic membrane, minimal button actuationforce providing greater device stability, and ensuring delivery systemactuation when the device tip is fully opposed to the tympanic membrane.

Other mechanisms or structure may be employed in lieu of, or inconjunction with, application of negative pressure to the tympanicmembrane, for elevation thereof For example, an adhesive or stickysubstance may be used, or a mechanical application using micro-barbs.

Tympanic Membrane Pressure Equalization Tube:

FIGS. 5A and 5B show a tympanic membrane pressure equalization tube 500,according to one embodiment of the invention. In this embodiment, thetube 500 is configured as a grommet made of silicone or some otherpliable elastomeric material and is intended to be placed within atympanic membrane to vent to the middle ear. Although a number ofsuitable pressure equalization tubes 500 may be used in conjunction witha delivery system as described above, in one embodiment the tube 500 mayhave an axial length of between about 2.0 mm and about 2.5 mm andideally about 2.3 mm. The tube 500 may have an inner diameter of about1.1 mm.

A central lumen 502 of the tube 500 is flanked by an integral medialflange 504 and lateral flange 506. The medial flange 504 and lateralflange 506 prevent the tube 500 from falling out of an opening createdin the tympanic membrane. In some embodiments, the lateral flange 504can be smaller in diameter than the medial flange 506, as shown, as thelateral flange 504 can be expanded within the tip 142 of the deliverysystem 100, while the medial flange is intended to expand distally pastthe tympanic membrane. In alternative embodiments, the lateral flange504 and medial flange 506 are of equal diameters. The exterior surfaceof the tympanic membrane equalization tube 500 includes optionalflexible zones 508 which facilitate straightening of the medial flange504 and lateral flange 506 for loading into a delivery system, as shownin FIG. 1P. The medial flange 504 and lateral flange 506 may alsoinclude optional notches or cutouts 504 a, 506 a which may furtherfacilitate straightening of the flanges 504, 506. FIG. 5C, depicts onesuch further embodiment containing 3 notches or cutouts 504 a and 506 aon each of the flanges 504, 506. Alternative embodiments may of coursecontain any combination of these optional notches or cutouts 504 a and506 a on the flanges, including having more notches on one flangecompared with the other flange and also including optional flexiblezones 508.

FIGS. 5D-5G show tympanic membrane pressure equalization tubes,according to other alternative embodiments of the invention. In someinstances, the flanges of the tube, when constrained within a deliverysystem in a straightened position for a long period of time as shown inFIG. 1P, may not spring back (i.e., expand into) their unconstrained,natural position quickly enough for effective delivery into the TM.Therefore, in some embodiments, internal scaffolding may be includedwithin the wall of the tube 510, 514, 518, 520 to help it reassume itsnatural shape. Such scaffolding may be constructed, for example, from asuper-elastic or shape-memory material, such as a nickel-titanium alloy,other metals, or polymers or other suitable materials. Also any of theseembodiments may include the optional flexible zones 508 described above.

FIG. 5D shows a tympanic membrane pressure equalization tube 510including an internal wire 512. The wire 512 provides a fast shaperecovery for the tube 510. FIG. 5E shows a tube 514 including aninternal double loop 516. The double loop 516 provides fast shaperecovery for the tube 514, especially for the flanges. FIG. 5F shows atube 518 including a plurality of wires 520. Using a plurality of wires520 ensures uniform shape recovery of the tube 518. FIG. 5G shows a tube520 including internal stent scaffolding 522, which promotes uniformshape recovery of the tube 520.

In many embodiments, the tympanic membrane equalization tubes disclosedherein can include features which help recover a misplaced tympanicmembrane equalization tube. A misplaced tympanic membrane equalizationtube located distally to the tympanic membrane can be especiallydifficult to remove. Such features can include tethers attached to anyportion of the tympanic membrane equalization tubes. The tethers can begrasped proximally to the tympanic membrane and used to pull themisplaced tympanic membrane equalization tube out of the ear.

The present invention may be embodied in other specific forms withoutdeparting from the essential characteristics thereof These otherembodiments are intended to be included within the scope of the presentinvention, which is set forth in the following claims.

1. A system for forming an incision in a tympanic membrane anddelivering a pressure equalization tube into the incision, the systemcomprising: a housing including a handle; an elongate shaft assemblycoupled with the housing, the shaft assembly comprising: an outer shafthaving a blunt distal tip portion a cutter linearly moveable within theouter shaft; a pusher slidably disposed over the cutter within the outershaft; a pressure equalization tube slidably disposed about the cutterat a distal end of the pusher; a shield slidably disposed over thepusher and the pressure equalization tube; and a dilator slidablydisposed over the shield; a cam assembly comprising: a cam shaftrotationally coupled within the housing, the cam shaft including a firstcam profile, a second cam profile, a third cam profile, and a fourth camprofile; a first cam follower moveably coupled to the first cam profile,the first cam follower attached to the cutter; a second cam followermoveably coupled to the second cam profile, the second cam followerattached to the pusher; a third cam follower moveably coupled to thethird cam profile, the third cam follower attached to the shield; afourth cam follower moveably coupled to the fourth cam profile, thefourth cam follower attached to the dilator; a spring biased between thehousing and the cam shaft, the spring having a wound position whichplaces a torsional load on the cam shaft, and a released position; and arelease member moveably coupled to the cam shaft, the release memberhaving a first position which maintains the spring in the wound positionand a second position which allows the spring to move into the releasedposition; wherein when the release member is moved into the releasedposition, the spring is released to move the cam shaft and cause the camfollowers to linearly move respective portions of the shaft assembly toform an incision in a tympanic membrane using the cutting member, dilatethe incision using the dilator, and advance the pressure equalizationtube out of the shield and into the incision using the pusher.
 2. Thesystem of claim 1, wherein the housing comprises a first housing portionand a second housing portion, and wherein each housing portion is amolded clamshell.
 3. The system of claim 2, wherein the housing portionsform a camshaft chamber, a cam follower chamber, a spring chamber, and atrigger mechanism chamber.
 4. The system of claim 1, wherein the outershaft is constructed from rigid tubing.
 5. The system of claim 1,wherein the outer shaft comprises an outer wall, an inner wall, and aspace therebetween in which negative pressure may be applied.
 6. Thesystem of claim 5, wherein the negative pressure may be used to actuatethe release member.
 7. The system of claim 1, wherein the cutting membercomprises an elongate wire with a diamond headed tip.
 8. The system ofclaim 1, wherein the shield comprises an elongate tube.
 9. The system ofclaim 1, wherein the pressure equalization tube comprises a grommet witha lumen, a medial flange, and a lateral flange.
 10. The system of claim9, wherein the medial and lateral flanges are compressed within theshield.
 11. The system of claim 10, wherein the pressure equalizationtube includes internal wire scaffolding.
 12. The system of claim 10,wherein the pressure equalization tube is constructed from anelastomeric material and includes flexible portions between the lumenand flanges.
 13. The system of claim 10, wherein the flanges includenotches that facilitate compression of the tube within the shield. 14.The system of claim 1, wherein the pusher comprises an elongate tube.15. The system of claim 1, wherein the dilator comprises an elongatetube with a distal tip, the distal tip being capable of expanding fromnarrow position to an open position.
 16. The system of claim 15, whereinthe distal tip comprises a plurality of members which are spring biasedin the narrow position and can be forcibly opened into the openposition.
 17. The system of claim 1, wherein the cam shaft comprises anelongate cylinder, with first and second ends rotationally attached tothe housing, a mid-section therebetween, and a spring holder extendingfrom the second end.
 18. The system of claim 15, wherein the camprofiles each comprise a patterned groove in the mid-section.
 19. Thesystem of claim 1, wherein the cam followers each comprise a block whichis slidably housed in the housing, each block including a drive pin forfollowing a respective cam profile.
 20. The system of claim 19, whereinthe blocks are arranged linearly with respect to the elongate shaft. 21.The system of claim 1, wherein a link couples the release member to thecamshaft, and wherein the release member pushes the link to release thecamshaft when moved into the second position.
 22. The system of claim 1,wherein a link couples the release member to the camshaft, and whereinthe release member, when moved laterally, releases the link to releasethe camshaft when moved into the second position.
 23. The system ofclaim 1, wherein the release member is selected from the groupcomprising a button, a trigger or a switch.
 24. A method for forming anincision and placing a pressure equalization tube in a tympanic membraneof an ear, the method comprising: contacting a blunt distal end of ashaft of a tube delivery device with a tympanic membrane; advancing acutter out of the shaft distal end to form an incision in the tympanicmembrane, wherein a dilator is disposed over at least a portion of thecutter; advancing a shield disposed over the cutter and within thedilator out of the shaft distal end and into the incision to dilate thedilator, wherein the shield is disposed over a pressure equalizationtube; retracting the cutter into the shaft; retracting the shield intothe shaft, thereby releasing a distal flange of the pressureequalization tube such that it assumes an expanded configuration; andpushing the pressure equalization tube out of the shield using a pusherdisposed within the shield, thereby releasing a proximal flange of thepressure equalization tube such that it assumes an expandedconfiguration; wherein, after being pushed out of the shield, a middleportion of the pressure equalization tube is disposed within theincision in the tympanic membrane and the distal and proximal flangesare disposed on opposite sides of the incision.
 25. The method of claim26, wherein the steps of retracting the shield and pushing theequalization tube occur simultaneously.
 26. The method of claim 24,wherein the advancing, retracting and pushing steps are initiated bypressing a button on the tube delivery device.
 27. The method of claim26, further comprising moving a safety member on the tube deliverydevice from an off position to an on position before pushing the button.28. The method of claim 26, further comprising removing a safety lockmember from the delivery device before pushing the button.
 29. Themethod of claim 24, wherein advancing the cutter comprises rotating acamshaft of the tube delivery device to a first cam position whichcauses a first cam follower to extend the cutter out of the outer shaftand also causes the fourth cam follower to extend the dilator out of theouter shaft.
 30. The method of claim 29, wherein advancing the shieldand retracting the cutter comprises rotating the camshaft to a secondcam position which causes a second cam follower to move the shield outof the shaft to expand a distal portion of the dilator and also causesthe first cam follower to move the cutting member back into the shaft.31. The method of claim 30, wherein retracting the shield comprisesrotating the camshaft to a third cam position which causes the secondcam follower to move the shield back into the outer shaft and alsocauses a fourth cam follower to move the dilator back into the outershaft, and also causes a third cam follower to move and push thepressure equalization tube partly out of the outer shaft.
 32. The methodof claim 31, wherein pushing the pressure equalization tube comprisesrotating the cam shaft to a final position which causes the third camfollower to further move the pusher and further push the pressureequalization tube partly out of the outer shaft.
 33. The method of claim32, wherein the cam shaft is rotated from the first position to thefinal position in a single continuous motion.
 34. The method of claim32, wherein the steps of pushing the pressure equalization tube andretracting the shield occur simultaneously.
 35. The method of claim 32,wherein contacting the blunt distal end comprises applying negativepressure to the tympanic membrane with the blunt distal end of the shaftto elevate the TM and enhance contact of the distal end of the shaftwith the tympanic membrane.
 36. The method of claim 35 wherein theapplied negative pressure actuates rotation of the camshaft.